Supplementary File: Definition of Complications

Microvascular flow and tissue oxygenation after major abdominal surgery: association with post-operative complications

Shaman Jhanji, Clement Lee, David Watson, Charles Hinds and Rupert M. Pearse.

Barts & The London School of Medicine and Dentistry, Queen Mary University of London, UK.

Supplementary File: Definition of complications

Infectious Complications

Sepsis, Severe sepsis and Septic shock

Two more of the following associated with documented infection (consensus definition):

i) core temperature <36 °C or >38 °C

ii) white cell count >12 x 109 l-1 or <4 x 109 l-1

iii) Respiratory rate >20 breaths per minute or PaCO2 < 4.5 kPa

iv) Pulse rate >90 bpm. Sepsis associated with organ dysfunction will be defined as severe sepsis. Sepsis associated with hypotension and need for vasopressors or inotropes despite fluid resuscitation will be defined as septic shock.

Urinary tract infection

A symptomatic urinary tract infection must meet at least one of the following criteria:

i) Patient has at least one of the following signs or symptoms with no other recognized cause: fever (>38 °C), urgency, frequency, dysuria, or suprapubic tenderness

And

patient has a positive urine culture, that is, >105 microorganisms per cm3 of urine with no more than two species of microorganisms.

ii) Patient has at least two of the following signs or symptoms with no other recognized cause: fever (>38 °C), urgency, frequency, dysuria, or suprapubic tenderness

And at least one of the following:

a. Positive dipstick for leukocyte esterase and/or nitrate

b. Pyuria (urine specimen with >10 WBC mm-3)

c. Organisms seen on Gram stain of unspun urine

d. At least two urine cultures with repeated isolation of the same uropathogen with >102 colonies/ mL in non-voided specimens

e. >105 colonies/mL of a single uropathogen in a patient being treated with an effective antimicrobial agent for a urinary tract infection

f. Physician diagnosis of a urinary tract infection

g. Physician institutes appropriate therapy for a urinary tract infection

Other infections of the urinary tract (kidney, ureter, bladder, urethra, etc)

Other infections of the urinary tract must meet at least one of the following criteria:

i) Patient has organisms isolated from culture of fluid (other than urine) or tissue from affected site.

ii) Patient has an abscess or other evidence of infection seen on direct examination, during a surgical operation, or during a histopathologic examination.

iii) Patient has at least two of the following signs or symptoms with no other recognized cause: fever (>38 °C), localized pain, or localized tenderness at the involved site

And at least one of the following:

a. Purulent drainage from affected site

b. Organisms cultured from blood that are compatible with suspected site of infection

c. Radiographic evidence of infection, for example, abnormal ultrasound, computed tomography or magnetic resonance imaging

d. Physician diagnosis of infection of the kidney, ureter, bladder, urethra, or tissues surrounding the retroperitoneal or perinephric space

e. Physician institutes appropriate therapy for an infection of the kidney, ureter, bladder, urethra, or tissues surrounding the retroperitoneal or perinephric space

Surgical site infection (superficial incisional)

A superficial SSI must meet the following criteria:

i) Infection occurs within 30 days after the operative procedure And involves only skin and subcutaneous tissue of the incision And patient has at least one of the following:

a. Purulent drainage from the superficial incision

b. Organisms isolated from an aseptically obtained culture of fluid or tissue from the superficial incision

c. At least one of the following signs or symptoms of infection: pain or tenderness, localized swelling, redness, or heat, and superficial incision is deliberately opened by surgeon, unless incision is culture-negative

d. Diagnosis of superficial incisional SSI by the surgeon or attending physician

Surgical site infection (deep incisional)

A deep incisional SSI must meet the following criteria:

i) Infection occurs within 30 days after the operative procedure if no implant is left in place or within 1 year if implant is in place and the infection appears to be related to the operative procedure

And involves deep soft tissues (e.g., fascial and muscle layers) of the incision

And patient has at least one of the following:

a. Purulent drainage from the deep incision but not from the organ/space component of the surgical site

b. A deep incision spontaneously dehisces or is deliberately opened by a surgeon when the patient has at least one of the following signs or symptoms: fever (>38C) or localized pain or tenderness, unless incision is culture-negative

c. An abscess or other evidence of infection involving the deep incision is found on direct examination, during reoperation, or by histopathologic or radiologic examination

d. Diagnosis of a deep incisional SSI by a surgeon or attending physician

An infection that involves both superficial and deep incision sites should be classified as a deep incisional SSI.

Surgical site infection (organ/space)

An organ/space SSI involves any part of the body, excluding the skin incision, fascia, or muscle layers, that is opened or manipulated during the operative procedure. Specific sites are assigned to organ/space SSI to further identify the location of the infection. Listed later are the specific sites that must be used to differentiate organ/space SSI. An example is appendectomy with subsequent sub-diaphragmatic abscess, which would be reported as an organ/space SSI at the intra-abdominal specific site. An organ/space SSI must meet the following criteria:

And infection involves any part of the body, excluding the skin incision, fascia, or muscle layers, that is opened or manipulated during the operative procedure

And patient has at least one of the following:

a. Purulent drainage from a drain that is placed through a stab wound into the organ/space

b. Organisms isolated from an aseptically obtained culture of fluid or tissue in the organ/ space

c. An abscess or other evidence of infection involving the organ/space that is found on direct examination, during reoperation, or by histopathologic or radiologic examination

d. Diagnosis of an organ/space SSI by a surgeon or attending physician

Laboratory confirmed bloodstream infection

Laboratory-confirmed bloodstream infection must meet at least one of the following criteria:

i) Patient has a recognized pathogen cultured from one or more blood cultures

And organism cultured from blood is not related to an infection at another site.

ii) Patient has at least one of the following signs or symptoms:

Fever (>38°C), chills, or hypotension

And at least one of the following:

a. Common skin contaminant is cultured from two or more blood cultures drawn on separate occasions

b. Common skin contaminant is cultured from at least one blood culture from a patient with an intravascular line, and the physician institutes appropriate antimicrobial therapy

c. Positive antigen test on blood

And signs and symptoms and positive laboratory results are not related to an infection at another site.

Nosocomial pneumonia

Ventilator-associated pneumonia (i.e. pneumonia in persons who had a device to assist or control respiration continuously through a tracheostomy or by endotracheal intubation within the 48-hour period before the onset of infection) will be classified separately. Care will be to distinguish between tracheal colonization, upper respiratory tract infections and early onset pneumonia. Nosocomial pneumonia will be characterized as early or late onset ie before or after first 4 days of hospitalization. Where repeated episodes of nosocomial pneumonia are suspected, a combination of new signs and symptoms and radiographic evidence or other diagnostic testing will be required to distinguish a new episode from a previous one.

Nosocomial pneumonia must meet the following criteria:

i) Two or more serial chest radiographs with at least one of the following:

a) New or progressive and persistent infiltrate

b) Consolidation

c) Cavitation

And at least one of the following:

a) Fever (>38°C) with no other recognized cause

b) Leucopaenia (<4,000 WBC mm-3) or leucocytosis (>12,000 WBC mm-3)

c) For adults >70 years old, altered mental status with no other recognized cause

And at least two of the following:

a) New onset of purulent sputum or change in character of sputum, or increased respiratory secretions, or increased suctioning requirements

b) New onset or worsening cough, or dyspnoea, or tachypnoea

c) Rales or bronchial breath sounds

d) Worsening gas exchange

Cardiovascular complications

Myocardial ischaemia or infarction

Acute ECG changes with appropriate clinical history and biochemical findings (cardiac troponin rise)

Arrhythmia

ECG evidence of rhythm disturbance resulting in hypotension or considered by clinical staff to be severe enough to require treatment

Cardiac or respiratory arrest

Clinical criteria according to UK Resuscitation Council guidelines

Limb or digital ischaemia

Sustained loss of arterial pulse (as determined by palpation or Doppler) or obvious gangrene

Respiratory Complications

Pulmonary oedema

Appropriate clinical history and examination with consistent chest radiograph

Pulmonary embolism

Computed tomography (CT) pulmonary angiogram with appropriate clinical history

Acute respiratory distress syndrome

According to consensus criteria:

i) Suitable precipitating condition (many causes exist)

ii) Acute onset diffuse bilateral pulmonary infiltrates on chest radiograph

iii) No evidence of cardiac failure or fluid overload (PAOP < 18 mmHg)

iv) Either

a) PaO2:FiO2 < 40 kPa = Acute Lung Injury

b) PaO2:FiO2 < 27 kPa = Acute Respiratory Distress Syndrome

Pleural effusions

Appropriate clinical history and examination with consistent radiograph, ultrasound or CT scan of the chest

Gastrointestinal Complications

Gastro-intestinal bleed

Unambiguous clinical evidence or endoscopy showing blood in gastro-intestinal tract

Bowel infarction

Demonstrated at laparotomy

Anastamotic breakdown

Demonstrated at laparotomy or by contrast enhanced radiograph or CT scan

Paralytic ileus

Persistent clinical evidence of intestinal ileus and failure to tolerate enteral fluid or feed associated with valid cause

Post-operative haemorrhage

Overt blood loss requiring transfusion of two or more units of blood in two hours.

Renal Complications

Acute renal failure

Oliguria (< 500 ml urine in 24 hours despite adequate hydration) with suitable changes in serum urea and creatinine from pre-operative values or requirement for renal replacement therapy

Neurological Complications

Stroke

Clinical diagnosis with confirmation by CT scan

Transient ischaemic attack

Clinical diagnosis